1. Field of the Invention
This invention relates to processes for preventing haze development in alcoholic and fruit beverages and, more particularly, to processes for removing haze precursors from such beverages by treatment with positively-charged media.
2. Description of the Prior Art
The development of haze in alcoholic and fruit beverages has long been a distinct problem. Development of haze in beverages is, of course, undesirable from the viewpoint of product aesthetics and eye-appeal. In addition, haze development can result in loss of product color as well as taste notes. Solution of this problem has been attempted by several different approaches. The most commonly employed method for coping with the haze problem in alcoholic beverages has been a procedure of reducing the temperatures of the beverage, e.g., beer, wine, whiskey, fortified wine products (sherry, brandy and cognac), rum, certain white and red wines, liquors and cordials, to cause haze formation at temperatures below about 45.degree. F. and most commonly at between about 20.degree. and 30.degree. F. During such chilling, the haze precursors apparently separate out as the so-called "haze" which can be then separated using known techniques such as filtration. In many cases, such treatment by chilling is not completely effective and several chilling and precipitation treatments may prove necessary. As an alternative to chill processing, attempts have been made to determine the amount of the precursors of haze in the grains employed in the production of specific beverages, e.g., by extraction of the malt employed in the production of beer. As a result of such determinations, grains of low haze-precursor content can be selected to produce beverages of low potential haze. Such procedures are costly and time-consuming. Although this approach can result in amelioration of the haze problem, it rarely can result in elimination thereof.
The haze problem has been investigated quite extensively but the exact nature of the haze has not been established. In beer, the formation of haze is attributed to the presence of phenolics as described, for example, in MBAA Technical Quarterly, Vol. 14, No. 4, 1977, p. 250, "Complex Phenols in Brewing--A Critical Survey" by R. J. Gardner and J. D. McGuinness, and The Brewers Digest, April, 1978, p. 36, "Determination of Phenolic Compounds in Beer and Brewing Materials" by Miroslar Dadic. In some whiskeys, haze is attributable to the presence of steroids which precipitate on chilling.
In fruit beverages, the haze problem has been treated primarily through the use of enzymes which hydrolyze the proteins which normally form haze with the phenolic components of the fruit preparation. Such beverages include, for example, apple, cranberry, grape, citrus fruit, peach, pear, plum, apricot and nectarine juices.
U.S. Pat. No. 3,958,023 to Butterworth describes a method for removing haze forming substances present in beer whereby a "chill control agent," e.g., polyvinylpyrrolidone, is added to a beer which, after a period of resting or aging at reduced temperature, e.g., five days to three months at temperatures of from about 30.degree. to 32.degree. F., is filtered to remove the chill control agent with the haze forming substances absorbed thereon. The requirement that the Butterworth liquid be in a chilled or refrigerated state prior to filtration prior to removal of the haze-forming components therefrom is clearly disadvantageous when it is considered that significant quantities of energy must be consumed in reducing the temperature of the liquid, in this case beer, to the level necessary for effective operation.
For the purpose of this disclosure, beverages to be treated in accordance with the invention are those derived from vegetable origin which form a haze on standing and/or chilling, i.e., are defined as unstable beverages. After treatment in accordance with the invention, the beverages form little, if any, haze under storage or chilling at the very least. The tendency towards haze formation is reduced as a result of treatment by the present process.